The fractal characteristics of earthquake dynamic gravity network in Northern China is researched and its fractal dimension D1=1.612 and the optimum gridding interval r=44 km are calculated respectively.From the perspective of fractal geometry,the ability of monitoring of Seismological Dynamic Gravity Network in North China is analyzed.The results show that the optimum interval approximates to the anomaly radius of gravity field change region,which is induced by earthquake of Ms=5.0;Gravity Network has good ability to monitor and predict the earthquake of Ms5.0.